Some people eat, sleep and chew gum, I do genealogy and write...

Monday, August 9, 2010

Scanners vs. Digital Cameras for preserving genealogical documents and photos

There are a number of ways to digitize documents and photographs. The two primary ways are to use some form of a scanner or in the alternative, some kind of digital camera. Following is a number of digital files of the same document acquired for the computer with different options. In each case the document was scanned or photographed at the optimal level for the device. The file was saved as a .tif file and the image was magnified to 200% of the original. The images are screen shots of the magnified original signatures.

Flatbed Scanner: The first scan was done with a ConoScan 8800F Flatbed Scanner which is advertised at 4800 x 9600dpi. The image is supposed to be 400 dpi from the scanner.  The file size was 17.9 MB.

High Speed Sheet Fed Scanner: The scan was done at 400 dpi on a Canon DR-4010C Scanner. The file size was 31.6 MB.

Newer Compact Digital Camera 12 Megapixels: This was done with a Canon A1100 IS. The file size was 3.2 MB.

Digital SLR Camera 15 Megapixels: This was done with a Canon 50D. The file size was 20.4 MB.

As you can see, all of the images are very readable and clear. The color change is a result of the lighting and can be corrected in Photoshop if needs be. Which one you pick really depends on the ultimate use of the image. If the image is being copied for content, then any one of the four are sufficient. However, if the copy is going to be used a substitute for the original for archive purposes, the flat bed scanner or the sheet fed scanner would be better images than the digital cameras. All of the images begin to pixelate at about 400% of normal size.

The purpose of this exercise was to graphically illustrate the ability to use digital cameras for archiving documents over the more traditional scanning methods. In case you think that the color cast on the camera images is objectionable, here is a gray scale version of the Digital SLR image:

For most purposes, digital cameras, even less expensive ones, are perfectly adequate to produce copies to be used as source material.


  1. I have often used my digital camera for copying images. I research a lot at the Carnegie Library in Pittsburgh, most of it is on microfilm.

    When you find something you want to copy you have to take the reel out, go to another part of the department, place it in another viewer, find the record, and finally copy the image.

    You just have to record on paper exactly where the information came from initially to identify the pictures.

  2. Great post about a topic, I have wondered about.

  3. I also use both scanners & digital camera to record. If a library has a reader-electronic scanner I use that for document images, and my camera to record the film box. Sometimes when I'm more rushed and the mf image is of something typed or more modern handwriting, I'll use my camera for the images because it's so much quicker.

    I'm happy with the image quality of my relatively inexpensive point and shoot Fuji for close up shots in natural light, but can see how a tripod would be very helpful for repetitive shots, same distance, lighting, etc. I get tired and it's difficult to avoid camera shake. Do you have suggestions for a tripod setup for recording documents?

    Are all scanners created equal? I mean, are 400 dpi images of the same document by different scanners equivalent in quality? I purchased a no frills inexpensive Epson scanner that would be easy to take with me and set up when I visit relatives and want to get scans of their photos & documents. Portability was important to me and it works fine as far as I can tell, but perhaps I should consider something "better" for my in-house projects (old letters, photos, diaries, etc).

    Thank you for your informative and thought-provoking blogs!